| Representative | Title | Presentation of credentials | Termination of mission | Appointed by |
| Solon Borland | Envoy Extraordinary and Minister Plenipotentiary | | April 17, 1854 | Franklin Pierce |
| Mirabeau B. Lamar | Minister Resident | September 14, 1858 | May 20, 1859 | James Buchanan |
| Alexander Dimitry | Minister Resident | September 29, 1859 | April 27, 1861 | James Buchanan |
| Charles N. Riotte | Minister Resident | August 29, 1861 | January 18, 1867 | Abraham Lincoln |
| Albert G. Lawrence | Minister Resident | January 18, 1867 | June 24, 1868 | Andrew Johnson |
| Jacob B. Blair | Minister Resident | October 6, 1868 | June 30, 1873 | Andrew Johnson |
| George Williamson | Minister Resident | August 13, 1873 | January 31, 1879 | Ulysses S. Grant |
| Cornelius A. Logan | Minister Resident | December 25, 1879 | April 17, 1882 | Rutherford B. Hayes |
| Henry Cook Hall | Envoy Extraordinary and Minister Plenipotentiary | November 22, 1882 | May 16, 1889 | Chester A. Arthur |
| Lansing B. Mizner | Envoy Extraordinary and Minister Plenipotentiary | August 30, 1889 | December 31, 1890 | Benjamin Harrison |
| Romualdo Pacheco | Envoy Extraordinary and Minister Plenipotentiary | May 7, 1891 | October 31, 1891 | Benjamin Harrison |
| Richard Cutts Shannon | Envoy Extraordinary and Minister Plenipotentiary | October 31, 1891 | April 30, 1893 | Benjamin Harrison |
| Lewis Baker | Envoy Extraordinary and Minister Plenipotentiary | May 20, 1893 | December 9, 1897 | Grover Cleveland |
| William L. Merry | Envoy Extraordinary and Minister Plenipotentiary | January 15, 1898 | March 4, 1911 | William McKinley |
| Lewis Einstein | Envoy Extraordinary and Minister Plenipotentiary | November 3, 1911 | December 29, 1911 | William H. Taft |
| Edward J. Hale | Envoy Extraordinary and Minister Plenipotentiary | August 29, 1913 | April 19, 1917 | Woodrow Wilson |
| Stewart Johnson | Chargé d'Affaires ad interim | April 19, 1917 | December 5, 1918 | Woodrow Wilson |
| John F. Martin, Jr. | Chargé d'Affaires ad interim | October 15, 1920 | January 1921 | Woodrow Wilson |
| Walter C. Thurston | Chargé d'Affaires ad interim | January 1921 | March 1922 | Warren G. Harding |
| Roy T. Davis | Envoy Extraordinary and Minister Plenipotentiary | March 14, 1922 | January 4, 1930 | Warren G. Harding |
| Charles C. Eberhardt | Envoy Extraordinary and Minister Plenipotentiary | March 14, 1930 | September 24, 1933 | Herbert Hoover |
| Leo R. Sack | Envoy Extraordinary and Minister Plenipotentiary | October 16, 1933 | January 10, 1937 | Franklin D. Roosevelt |
| William H. Hornibrook | Envoy Extraordinary and Minister Plenipotentiary | September 2, 1937 | September 1, 1941 | Franklin D. Roosevelt |
| Arthur Bliss Lane | Envoy Extraordinary and Minister Plenipotentiary | October 27, 1941 | March 17, 1942 | Franklin D. Roosevelt |
| Robert M. Scotten | Envoy Extraordinary and Minister Plenipotentiary | March 31, 1942 | April 20, 1943 | Franklin D. Roosevelt |
| Fay Allen Des Portes | Ambassador Extraordinary and Plenipotentiary | May 20, 1943 | September 11, 1944 | Franklin D. Roosevelt |
| Hallett Johnson | Ambassador Extraordinary and Plenipotentiary | February 14, 1945 | May 16, 1947 | Franklin D. Roosevelt |
| Walter J. Donnelly | Ambassador Extraordinary and Plenipotentiary | June 27, 1947 | October 15, 1947 | Harry S. Truman |
| Nathaniel Penistone Davis | Ambassador Extraordinary and Plenipotentiary | January 31, 1948 | June 8, 1949 | Harry S. Truman |
| Joseph Flack | Ambassador Extraordinary and Plenipotentiary | August 13, 1949 | September 21, 1950 | Harry S. Truman |
| Philip Bracken Fleming | Ambassador Extraordinary and Plenipotentiary | November 20, 1951 | August 7, 1953 | Harry S. Truman |
| Robert C. Hill | Ambassador Extraordinary and Plenipotentiary | November 4, 1953 | September 10, 1954 | Dwight D. Eisenhower |
| Robert F. Woodward | Ambassador Extraordinary and Plenipotentiary | December 3, 1954 | March 15, 1958 | Dwight D. Eisenhower |
| Whiting Willauer | Ambassador Extraordinary and Plenipotentiary | May 5, 1958 | April 17, 1961 | Dwight D. Eisenhower |
| Raymond Telles | Ambassador Extraordinary and Plenipotentiary | May 22, 1961 | February 19, 1967 | John F. Kennedy |
| Clarence A. Boonstra | Ambassador Extraordinary and Plenipotentiary | March 8, 1967 | August 11, 1969 | Lyndon B. Johnson |
| Walter C. Ploeser | Ambassador Extraordinary and Plenipotentiary | April 27, 1970 | April 13, 1972 | Richard Nixon |
| Viron P. Vaky | Ambassador Extraordinary and Plenipotentiary | October 17, 1972 | February 9, 1974 | Richard Nixon |
| Terence A. Todman | Ambassador Extraordinary and Plenipotentiary | March 17, 1975 | January 24, 1977 | Gerald Ford |
| Marvin Weissman | Ambassador Extraordinary and Plenipotentiary | June 28, 1977 | March 22, 1980 | Jimmy Carter |
| Francis J. McNeil | Ambassador Extraordinary and Plenipotentiary | July 8, 1980 | June 27, 1983 | Jimmy Carter |
| Curtin Winsor, Jr. | Ambassador Extraordinary and Plenipotentiary | July 14, 1983 | February 18, 1985 | Ronald Reagan |
| Lewis Arthur Tambs | Ambassador Extraordinary and Plenipotentiary | August 1, 1985 | January 1, 1987 | Ronald Reagan |
| Deane Roesch Hinton | Ambassador Extraordinary and Plenipotentiary | November 17, 1987 | January 4, 1990 | Ronald Reagan |
| Luis Guinot, Jr. | Ambassador Extraordinary and Plenipotentiary | August 27, 1991 | March 1, 1993 | George H. W. Bush |
| Robert O. Homme | Chargé d'Affaires ad interim | March 1, 1993 | July 1993 | Bill Clinton |
| Donald Harrington | Chargé d'Affaires ad interim | July 1993 | August 1993 | Bill Clinton |
| Joseph Becelia | Chargé d'Affaires ad interim | August 1993 | October 21, 1994 | Bill Clinton |
| Peter Jon de Vos | Ambassador Extraordinary and Plenipotentiary | October 21, 1994 | October 14, 1997 | Bill Clinton |
| Thomas J. Dodd, Jr. | Ambassador Extraordinary and Plenipotentiary | November 26, 1997 | March 1, 2001 | Bill Clinton |
| John J. Danilovich | Ambassador Extraordinary and Plenipotentiary | October 10, 2001 | June 1, 2004 | George W. Bush |
| Mark Langdale | Ambassador Extraordinary and Plenipotentiary | November 8, 2005 | July 31, 2007 | George W. Bush |
| Peter M. Brennan | Chargé d'Affaires ad interim | August 1, 2007 | May 5, 2008 | George W. Bush |
| Peter Cianchette | Ambassador Extraordinary and Plenipotentiary | May 5, 2008 | June 19, 2009 | George W. Bush |
| Anne S. Andrew | Ambassador Extraordinary and Plenipotentiary | January 12, 2010 | June 12, 2013 | Barack Obama |
| S. Fitzgerald Haney | Ambassador Extraordinary and Plenipotentiary | July 8, 2015 | July 15, 2017 | Barack Obama |
| Sharon Day | Ambassador Extraordinary and Plenipotentiary | September 25, 2017 | January 20, 2021 | Donald Trump |
| Cynthia Telles | Ambassador Extraordinary and Plenipotentiary | March 11, 2022 | January 20, 2025 | Joe Biden |
| Mike Flores | Chargé d'Affaires ad interim | January 20, 2025 | August 1, 2025 | Donald Trump |
| Jennifer Savage | Chargé d'Affaires ad interim | August 5, 2025 | January 5, 2026 | Donald Trump |
| Melinda Hildebrand | Ambassador Extraordinary and Plenipotentiary | January 8, 2026 | Incumbent | Donald Trump |